1. Field of the Invention
The present invention relates to a process for effectively producing the magnesium salt of sulfonic acids and sulfuric esters suitable for use as a surface-active agent.
2. Description of the Prior Art
The sodium salt of sulfonic acids and sulfuric esters has heretobefore been well-known as a surface-active agent. Recently, the magnesium salt of sulfonic acids and sulfuric esters has become of major interest as a surface-active agent having an excellent frothing property. The simplest known method for producing the magnesium salt of sulfonic acids or sulfuric esters is a metathesis process or a double-decomposition process, in which the sodium salt of organic sulfonic acids or sulfuric esters is reacted with any water-soluble magnesium compound. However, this method is not recommendable due to the fact that large quantities of by-products are necessarily produced. On the other hand, methods in which organic sulfonic acids and sulfuric esters are neutralized with magnesium oxide or magnesium hydroxide are known. These methods have an advantage that no by-product is formed. However, these methods have a disadvantage that, since magnesium oxide and magnesium hydroxide to be used as a neutralizing agent are only slightly soluble in water, a long period neutralization operation is required.